Dogs mount for a number of reasons, not just because they want to mate. It is most common in entire males between one and two-years-old, but neutered males and bitches also mount. It may be a sign of wanting to dominate another dog, but not always, and may just be overexcitement, often coupled with being socially inept.

If your dog is a mounter, be considerate to others, and don't let him off the lead with people or dogs he could frighten, especially smaller dogs. Some dogs can handle mounters, and just issue a brief reprimand, other dogs find it scary. Explain your problem if another owner suggests letting your and their dogs off together, and be prepared to deal with any attempts to mount. Work on a solid recall, so you can call your dog from a distance. Watch your dog's body language when he meets another dog, to spot the signs that he is likely to mount. Call him and put him on the leash if he looks like he is about to. You can use a water pistol on a persistent mounter - it doesn't have to be very strong to be effective.

Dogs mount humans too. Treat this as an over-enthusiastic jumping up. Dogs that mount are also dogs that jump up, so deal with the jumping up, and the mounting takes care of itself. Again, a weak water pistol may be needed to reinforce the 'off' command if the dog is too engrossed to pay you attention. A dog that mounts people can seriously frighten children and frail older people, so don't let him do it, ever, even if it looks comic. Mounting inanimate objects is less of a problem, because many dogs do this and never mount other dogs or humans.

Dogs can get turned on by certain perfumes, and if they are in human shampoos, they may show an overaffectionate interest in the human head. When a dog has been shampood using perfumes that turn dogs on, the dog may also attract mounters. This effect is temporary, and disappears once the smell of the shampoo is dissipated. Choose your shampoos carefully!